UPSHUR, the United States, Jan. 3 (Xinhuanet) -- Rescuers have found the body of one of 13 miners who have been trapped underground in an eastern U.S. coal mine for over 36 hours, the mine's owner said Tuesday.

    Ben Hatfield, president of International Coal Group, which ownsthe Sago Mine in the Upshur county, West Virginia, told reporters that the rescuers will continue to search for other trapped miners.

    "Our efforts move forward as quickly as we can, and we're fervently determined to do our very best to get to them," he said.

    Hatfield said rescue crews had reached some 3,400 meters into the mine shaft, and will get to the position where the rest of theminers are believed to be located within several hours.

    He said the rescue effort will end "only when all hope is lost."

    The miners were trapped early Monday after an explosion of unknown origin.

    Since Tuesday afternoon, rescuers have accelerated their efforts to locate the miners by starting to bore two new vertical shafts for their probes.

    Efforts also were being made to advance horizontally into the Sago Mine.

    However, rescuers abandoned a plan to move in a camera-equippedtrack-mounted robot with sensors to measure air quality, after it was bogged down in mud inside the mine.

    U.S. media said the Sago Mine was cited 208 times over alleged safety violations in 2005, up from 68 citations the year before.

    Federal regulators' allegations against the Sago Mine included failure to dilute coal dust, which can lead to explosions, and failure to properly operate and maintain machinery. Enditem